Microbial contamination of contact lens cases among medical students.

PURPOSE: We performed a systematic examination of the rate and level of contamination of contact lens cases in a population of asymptomatic contact lens wearers using commercially prepared chemical disinfection solutions.

METHODS

Solutions from the lens cases and from the conjunctiva of 21 asymptomatic contact lens wearers were examined.

RESULTS

Contamination was found in five (24%) of the lens cases; four of the isolated microorganisms were recognized as potential ocular pathogens, namely Xanthomonas maltophilia, Pseudomonas cepacia, Serratia liquefaciens, and Serratia plymuthica. Serratia organisms have not been previously isolated from lens care solutions preserved with guanide, and, in addition, this was the first time that Serratia plymuthica has been isolated from a lens care system. Acanthamoeba was not detected in any of the examined samples, and no potential pathogens were isolated from the conjunctiva. Among students having contaminated lens cases, all reported problems such as itching, redness, dryness, and coating of the lens.

CONCLUSIONS

The percentage of contaminated lens cases in this study was lower than in other studies. However, since the microorganisms identified in 80% of the contaminated lens cases were considered potential ocular pathogens, we feel contact lens wearers should be encouraged to frequently replace their lens cases.